1. Field of the Invention
The present invention relates to variable displacement compressors used in automobile air-conditioning apparatuses.
2. Description of the Related Art
There are a variety of compressors that may be provided to air-condition the passenger's compartment of an automobile. One of these compressors is described in Japanese Unexamined Patent Publication 06-288347. In this publication, a variable displacement compressor shown in FIG. 7 is provided with a hinge mechanism K which allows inclination of a swash plate 14. The hinge mechanism K includes a support arm 17, which projects in a rearward direction from a rotor 16, and a guide pin 18, the basal end of which is fixed to the swash plate 14.
The support arm 17 has a round receptacle 50. The axis of the receptacle 50 extends along an imaginary plane that includes the axis O of a drive shaft 6. A spheric body 18a is provided on the distal end of the guide pin 18. The spheric body 18a fits into the receptacle 50. The spheric body 18a comes into linear contact with the wall of the receptacle 50 as it moves inside the receptacle 50 and pivots with respect to the axis O. This enables inclination of the swash plate 14. When a piston 10 causes suction or compression of gas, a moment acts on the swash plate 14. The moment is carried by the spheric body 18a.
The linear contact between the spheric body 18a and the wall of the receptacle 50 results in high contact pressure. When the load of the compressor becomes high, alteration of the compressor displacement increases abrasion between the spheric body 18a and the wall of the receptacle 50. To reduce such abrasion, the hinge mechanism K is provided with a pair of shoes 40. As shown in FIG. 8, the pair of shoes 40 define a cylindrical body. The cylindrical body is divided axially into halves with each half defining one of the shoes 40. The inner surface of each shoe 40 comes into spheric surface contact with the spheric body 18a while the outer surface of each shoe 40 comes into cylindrical surface contact with the wall of the receptacle 50.
Since this structure avoids linear contact, abrasion between the spheric body 18a and the wall of the receptacle 50 is reduced. However, the spheric body 18a must be retained between the shoes 40 before fitting them into the receptacle 50. Thus, it is required that the shoes 40 retaining the spheric body 18a be held either manually or by some sort of holder when assembling them in the receptacle 50. Furthermore, a holder would interfere with the advancement of the shoes 40 in the receptacle 50. As a result, assembly was burdensome.